A hand held cutting machine such as a cut-off saw, chain saw, a clearing saw or the like working at high speeds is often equipped with a safety arrangement on the rear handle laid out such that when the operator releases his grip or removes his hand from the handle the machine throttle returns to idle and the machine slows down towards idle speed. This slow down takes a certain time depending on the speed and rotational energy of the rotating tool as well as of the losses of the transmission between engine and tool and also the braking power of the engine. A cutting machine driven by an internal combustion engine usually has a centrifugal clutch that disengages the engine below an engagement speed. Below this speed there is therefore no braking power from the engine, and thus slowing down of the rotating tool is especially slow, i.e. takes especially long time. Hitherto, a cutting machine has been provided with a driving belt of the kind named V-belt having a considerable energy loss but nowadays such machines are often equipped with a belt which has a considerably smaller thickness and thereby a reduced energy loss, e.g. a poly-v belt. The reduced energy loss however also brings one drawback. The retarding function is much smaller compared to the traditional V-belt. Therefore the slowing down towards idle speed takes even more time. Therefore a separate retarding device could be an advantage. There are mainly two ways to retard, namely by means of manually controlled retarding devices which are actuated by the user or by means of automatically controlled retarding devices which are actuated by a retarding unit when the grip of the rear handle is released. The provision of such a mechanism makes the machine less secure in the case of a manually controlled retarding device and very complicated as to its design in the case of an automatically controlled retarding device. A cut off saw must be regarded as a hand held cutting machine even if it can be attached to a trolley. Its main use is a hand held machine.